Y khoa, y dược - The skeleton: Part C

7 The Skeleton: Part CAppendicular SkeletonBones of the limbs and their girdlesPectoral girdle attaches the upper limbs to the body trunkPelvic girdle secures the lower limbsPectoral Girdle (Shoulder Girdle)Clavicles and the scapulaeAttach the upper limbs to the axial skeleton Provide attachment sites for muscles that move the upper limbsPLAYA&P Flix™: Bones of the pectoral girdleFigure 7.24aClavicleAcromio-clavicularjointScapula(a)Articulated pectoral girdleClavicles (Collarbones)Flattened acromial (lateral) end articulates with the scapulaCone-shaped sternal (medial) end articulates with the sternumAct as braces to hold the scapulae and arms out laterally Figure 7.24bAcromial (lateral)end(b)Right clavicle, superior viewPosteriorSternal (medial)endAnteriorScapulae (Shoulder Blades)Situated on the dorsal surface of rib cage, between ribs 2 and 7Flat and triangular, with three borders and three anglesSeven large fossae, named according to locationFigure 7.25aAcromionCoracoidprocessSuprascapular notchSuperior borderSuperiorangleSubscapularfossaMedial borderInferior angleGlenoidcavityLateral border(a) Right scapula, anterior aspectFigure 7.25bSuperiorangleMedial borderCoracoid processSuprascapular notchAcromionGlenoidcavityat lateralangleLateral borderInfraspinousfossaSpine(b) Right scapula, posterior aspectSupraspinousfossaFigure 7.25cCoracoidprocessGlenoidcavityAcromionInfraspinousfossaSpine(c) Right scapula, lateral aspectInfraglenoidtubercleSupraglenoidtubercleSupraspinous fossaSubscapularfossaInferior angleSupraspinousfossaInfraspinousfossaSubscapularfossaPosteriorAnteriorThe Upper Limb30 bones form the skeletal framework of each upper limbArmHumerusForearmRadius and ulnaHand8 carpal bones in the wrist5 metacarpal bones in the palm14 phalanges in the fingers HumerusLargest, longest bone of upper limbArticulates superiorly with glenoid cavity of scapulaArticulates inferiorly with radius and ulnaFigure 7.26aGreatertubercleLessertubercleInter-tubercularsulcusLateralsupracondylarridgeRadialfossaCapitulumHead ofhumerusAnatomicalneckDeltoidtuberosity CoronoidfossaMedialepicondyleTrochlea(a) Anterior viewBones of the ForearmUlnaMedial bone in forearm Forms the major portion of the elbow joint with the humerusRadiusLateral bone in forearmHead articulates with capitulum of humerus and with radial notch of ulnaInterosseous membrane connects the radius and ulna along their entire lengthFigure 7.27a-bRadialnotch ofthe ulnaOlecranonprocessTrochlearnotchCoronoidprocess ProximalradioulnarjointDistal radioulnarjointStyloid processof radiusRadiusNeck ofradiusHead ofradiusUlnar notchof the radiusHead of ulnaStyloidprocess of ulna InterosseousmembraneUlnaHeadNeckRadialtuberosityRadiusStyloidprocessof radius(a) Anterior view(b) Posterior viewFigure 7.27c-d(c) Proximal portion of ulna, lateral view Olecranon processTrochlear notchCoronoid processRadial notchView(d) Distal ends of the radius and ulna at the wrist Ulnar notch of radiusHeadof ulna StyloidprocessArticulationfor scaphoidArticulationfor lunateStyloidprocessViewFigure 7.26c-dCoronoidfossa RadiusRadialtuberosityHead ofradiusCapitulumTrochlea(c) Anterior view at the elbow regionHumerusMedialepicondyleCoronoidprocess of ulnaUlnaRadial notchOlecranonfossaUlnaOlecranonprocessMedialepicondyle(d) Posterior view of extended elbowHumerusLateralepicondyleHeadRadiusNeckHand: CarpusEight bones in two rowsProximal rowScaphoid, lunate, triquetrum, and pisiform proximallyDistal rowTrapezium, trapezoid, capitate, and hamate distallyOnly scaphoid and lunate articulate with radius to form wrist jointHand: Metacarpus and PhalangesMetacarpusFive metacarpal bones (#1 to #5) form the palmPhalangesEach finger (digit), except the thumb, has three phalanges—distal, middle, and proximalFingers are numbered 1–5, beginning with the thumb (pollex)Thumb has no middle phalanxFigure 7.28a-b• Trapezoid• Trapezium• ScaphoidPhalangesCarpalsRadius• Proximal• Middle• Distal• Triquetrum• Lunate• Capitate• Hamate• PisiformMetacarpalsCarpals(b) Posterior view of left handUlna• Base• Shaft• Head• Trapezoid• Trapezium• ScaphoidCarpals(a) Anterior view of left handRadiusSesamoidbonesPelvic (Hip) GirdleTwo hip bones (each also called coxal bone or os coxae)Attach the lower limbs to the axial skeleton with strong ligamentsTransmit weight of upper body to lower limbsSupport pelvic organsEach hip bone consists of three fused bones: ilium, ischium, and pubisTogether with the sacrum and the coccyx, these bones form the bony pelvisFigure 7.29Coxalbone(os coxaeor hip bone)lliumSacroiliacjointIliac fossaPubicbone IschiumSacrumBase of sacrumSacralpromontoryPelvic brimAcetabulumPubic crestPubic symphysisIliac crestCoccyxPubic archAnterior inferioriliac spine Anteriorsuperior iliac spinePubic tuberclePLAYAnimation: Rotatable pelvisHip BoneThree regionsIliumSuperior region of the coxal boneAuricular surface articulates with the sacrum (sacroiliac joint)IschiumPosteroinferior part of hip bonePubisAnterior portion of hip boneMidline pubic symphysis jointFigure 7.30aIliumAlaAnterior gluteallinePosterior gluteal linePosteriorsuperioriIiac spineGreater sciaticnotchPosterior inferioriliac spineIschial bodyIschial spineLesser sciatic notchIschialtuberosityIschiumIschial ramusObturator foramenInferiorgluteal lineAcetabulumPubic bodyIliac crestAnteriorsuperioriliac spineAnterior inferioriliac spinePubisInferior ramusof pubis(a) Lateral view, right hip boneFigure 7.30bIliac fossaIliumIliac crestAnteriorsuperioriliac spineAnterior inferioriliac spineArcuate linePubic tubercleSuperior ramusof pubisInferior ramusof pubisPosteriorsuperioriliac spineObturatorforamenBody ofthe iliumIschiumIschial ramus(b) Medial view, right hip boneAuricularsurfaceIschial spineLesser sciatic notchGreater sciatic notchPosteriorinferioriliac spineArticular surfaceof pubis (at pubic symphysis)Comparison of Male and Female PelvesFemale pelvisAdapted for childbearingTrue pelvis (inferior to pelvic brim) defines birth canalCavity of the true pelvis is broad, shallow, and has greater capacityComparison of Male and Female PelvesMale pelvisTilted less forwardAdapted for support of male’s heavier build and stronger musclesCavity of true pelvis is narrow and deepComparison of Male and Female PelvesCharacteristicFemaleMaleBone thicknessLighter, thinner, and smootherHeavier, thicker, and more prominent markingsPubic arch/angle80˚– 90˚50˚– 60˚AcetabulaSmall; farther apartLarge; closer togetherSacrumWider, shorter; sacral curvature is accentuatedNarrow, longer; sacral promontory more ventralCoccyxMore movable; straighterLess movable; curves ventrallyTable 7.4Table 7.4Table 7.4The Lower LimbCarries the weight of the bodySubjected to exceptional forces Three segments of the lower limbThigh: femurLeg: tibia and fibulaFoot: 7 tarsal bones in the ankle, 5 metatarsal bones in the metatarsus, and 14 phalanges in the toesFemurLargest and strongest bone in the bodyArticulates proximally with the acetabulum of the hip and distally with the tibia and patellaFigure 7.31NeckFoveacapitisGreatertrochanterInter-trochantericcrestHeadIntertrochantericlineLesser trochanterGluteal tuberosityLinea asperaLateralcondyleLateralepicondyleIntercondylar fossaMedial andlateral supra-condylar linesMedial condyleMedialepicondyleAdductortubercle Anterior viewPosterior view(b) Femur (thigh bone)Lateral epicondylePatellar surfacePosteriorFacet formedialcondyleof femurFacet for lateralcondyle of femurSurface forpatellarligamentApexAnterior(a) Patella (kneecap)Bones of the LegTibiaMedial leg boneReceives the weight of the body from the femur and transmits it to the footFibulaNot weight bearing; no articulation with femurSite of muscle attachment Connected to tibia by interosseous membraneArticulates with tibia via proximal and distal tibiofibular jointsFigure 7.32aMedial condyleArticular surfaceTibial tuberosityInterosseous membraneAnterior borderTibiaMedial malleolusIntercondylar eminenceProximal tibiofibularjointDistal tibiofibularjointLateral malleolusLateral condyleFibulaHead(a) Anterior viewFigure 7.32bMedial condyleArticular surface oflateral condyleArticular surfaceof medial condyle Articular surfaceInterosseousmembrane TibiaFibulaHead of fibulaMedial malleolusLateral malleolus(b) Posterior viewFoot: TarsalsSeven tarsal bones form the posterior half of the footTalus transfers most of the weight from the tibia to the calcaneusOther tarsal bones: cuboid, navicular, and the medial, intermediate, and lateral cuneiformsFoot: Metatarsals and PhalangesMetatarsals:Five metatarsal bones (#1 to #5) Enlarged head of metatarsal 1 forms the “ball of the foot”PhalangesThe 14 bones of the toesEach digit (except the hallux) has three phalanges Hallux has no middle phalanxFigure 7.33aMedialcuneiformPhalangesMetatarsalsTarsalsNavicularIntermediatecuneiformTalusCalcaneus(a) Superior viewCuboidLateralcuneiformProximal54321MiddleDistalTrochleaof talusFigure 7.33bFacet formedialmalleolusCalcanealtuberosity(b) Medial viewIntermediatecuneiformSustentac-ulum tali(talar shelf)TalusNavicularFirst metatarsalMedialcuneiformCalcaneusPLAYAnimation: Rotatable bones of the footArches of the FootArches are maintained by interlocking foot bones, ligaments, and tendonsArches allow the foot to bear weightThree archesLateral longitudinal Medial longitudinal Transverse Figure 7.34aMedial longitudinalarch Transverse archLaterallongitudinal arch(a) Lateral aspect of right footDevelopmental Aspects: Fetal SkullInfant skull has more bones than the adult skullSkull bones such as the mandible and frontal bones are unfused At birth, skull bones are connected by fontanellesFontanellesUnossified remnants of fibrous membranes between fetal skull bonesFour fontanelles Anterior, posterior, mastoid, and sphenoidFigure 7.35Frontal boneOssificationcenterOccipital bone(a) Superior viewPosterior fontanelle Parietal boneAnteriorfontanelleFrontal suture(b) Lateral viewPosteriorfontanelle Mastoidfontanelle Parietal boneOssificationcenterOccipital boneTemporal bone(squamous portion) Frontal boneSphenoidalfontanelleDevelopmental Aspects: Growth Rates At birth, the cranium is huge relative to the faceAt 9 months of age, cranium is ½ adult sizeMandible and maxilla are foreshortened but lengthen with ageThe arms and legs grow at a faster rate than the head and trunk, leading to adult proportionsDevelopmental Aspects: Spinal CurvatureThoracic and sacral curvatures are obvious at birthThese primary curvatures give the spine a C shapeConvex posteriorlyFigure 7.37Developmental Aspects: Spinal CurvatureSecondary curvaturesCervical and lumbar—convex anteriorlyAppear as child develops (e.g., lifts head, learns to walk)Developmental Aspects: Old AgeIntervertebral discs become thin, less hydrated, and less elasticRisk of disc herniation increasesLoss of stature by several centimeters is common by age 55 Costal cartilages ossify, causing the thorax to become rigidAll bones lose mass